Hermetically-sealed dry cell



5. w. HEI SE' HERMETICALLY. SEALED DRY CELL Filed Jun'e 5Q. 1921 till)hil l' atented Sept. 23, 1.924.

unit-no s'rarrs intern rn'rsnr 'QFFlCbZ.

GEORGE W. HEISE, F ELMHURST, NEW YORK, ASSIGNOH, T0 NATIONAL CARBONcomrenv, mo,

A CORPORATION OF NEW YORK.

HEEMETICALLY-SEALED DRY CELL.

Application filed June 30, 1921. Serial No. 481,715.

To all whom it may concern Be it-knovvn that l, GEORGE WV. Hnisn,a-citizen of the United States, residing at Elmhurst, in the county of'Queens and State of New York, have invented certain new and useful lmrovements in Hermetically-Sealed Dry ells, of which the following is aspecification.

.Tlhis invention relates in general to the prevention of detrimental gaspressure in dry cells. More specifically, it comp-rises the use ofreagents capable of fixing gases evolved in hermetically sealed cellsdurin 'their storage or shelf-life period.

it is known that the pro-service deterioration of -dry cells is due inlarge part to the non-hermetic character of the seal. Moisturecontinuously escapes through crevices between the seal and theelectrodes or through the pores of the carbon rod, and it is probablealso that air enters throu h these openings, increasing zinc corrosionby depolarizing the centers of local action.

lt'leretofore it has been regarded as impracticable to provide a truehermetic seal on dry cells of standard construction and reagentcomposition because of the evolution of ga es,- position of the mix, orother causes. nless these gases find an exit, the internal pressure maybecome sufficient to distort or rupture some portion of the cell. It isan object of the present invention to provide a hermetically sealed cellin which the generation of excessive gas pressure is prevented. Thisobject is. attained. by scaling to the cell a removable impervious capwhich may be so constructed as to form an expansion chamber havingavolume adequate to receive cell gases Without an excessive developmentof pressure.

Reagents capable of fixing the evolved gases in the form oi compoundshaving low vapor pressure at ordinary temperature may be used in suchcap-s as an additional protection against the accumulation of gases. Ur,when the reagent employed is an active absorbent, it maybe supplied in asealing cap of relatively small volume.

The invention will. be described in detail in connection with theaccompanying drawrug, in whichig. l is a vertical longitudinal sectionthrough a hermetically sealed cell,

due to local action, decom- Fig. 2 is a fragmentary side elevationshowing the sealing means, and

Fig. 3 is a vertical longitudinal section through a cell having amodified form of cap Which contains agas absorbent.

Reference numeral 1 denotes a zinc con tainer, 2 a lining of bibulousmaterial and 3 a mix bobbin containing a carbon rod 4. The zinccontainer has a marginal depression 5 to which a binding post may beattachedso as to lie Wholly Within the outline of the container. Aplastic seal 6 of the usual type is provided. This seal is nonhermeticbut-is sufficiently close fitting to prevent undue evaporation ofmoisture after the removal of the absolutely airtight closure now to bedescribed.

The hermetic seal comprises a cap 7, of metal or other imperviousmaterial, having a cross section corresponding to that of thecontainer 1. The cap and container, placed with their margins inabutting relation, are secured together by means of a band 8 overlyingtheir junction. The band 8 may be attached in any manner Which will givea secure and air-tight joint, as, for example, by soldering it to boththe cap and container. A tongue 9 is provided on the band 8 'and'is'adapted to be passed through an opening 10 in key 11. When it is desiredto remove the hermetic sealing cap 7 the band may be severed by engagingthe tongue in the key and rotating the latter to tear the metal alongthe lines of the sides of the tongue extended, in a Well known manner. Aclip 12 may be provided on the to of cap 7, or elsewhere on the cell,for hoding the key in handy position.

The cap preferably has a volume about five times as large as the volumeoi gas, measured at atmospheric temperature and pressure, which willnormally be evolved from the cell contents. Experience has shown that acap about 1 inches in height is suitable for application to 6 inch cell,and the same relative proportions may be used in sealed cells of othersizes. The volume of a cap of this type is relatively very largeas'compared to the interstitial volume below the pitch inner seal. F nchan expansion chamber is capable of receiving without undue strain aquantity of which would exert a distorting or. disrupt ing pressure iiconfined below the inner seal. The cap is preferably made of thinnermetal than the usual zinc can and is formed with a concave top which canspring outwardly into convex shape to enlarge the ex pansion chamber,should the pressure of the gas require it.

of gas pressure in hermetically sealed cells is the formation of carbondioxid b interaction ofthe mix and electrolyte. ilocal action upon thezinc is substantially prevented by sealing the cell from contact withair, so that the hydrogen production is negligible. As carbon dioxid isthe only gas which under ordinary conditions is likely to causeexcessive ressure, hermetically sealed cells maybe adiiquately protectedby the use of an alkaline absorbent. Hydrated lime may be mentione byway of example, as a suitable material. A large number of alkalinesolids capable of reacting with carbon dioxid at ordinary temperaturesare known, however, and my invention includes the use of anv of thesebodies.

As shown in Fig. 3, a cap 13 is sealed upon a cell in the mannerdescribed above. A material 14, such as lime, is contained in I havediscovered that the principal cause the cap and is preferably spacedfrom the carbon electrode by an heavy paper or the like.

line liquids as absorbents of'carbon dioxid is also within the scope ofmy invention. When these are used, any suitable precautions may be takento prevent electrical conmotion between the carbon and zinc inverted cup15 of The use of alkapoles.

Another convenient way dioxid is by the use of ammonia gas. may beintroduced into the of ways,

This cap in a variety for example by evacuating the cap through asuitable opening, passing in ammonia, and sealing the opening. Carbondioxid evolved from, the mix will pass through crevices between theplastic seal 6 and the electrodes, or through pores in the carbon rodand spacing cup 15, into contact and combination with the ammonia, lime,or other absorbent.

Instead of supplying a material capable of reacting with carbon dioxid,the same ultlmate result may be obtained by the use of any gas or vaporwhich will react chemically with a the cell to produce a solid genproduced by local action on the zinc,

the corrosion of the metal being accelerated by the presence of theoxygen, or it may be fixed in other ways, as by the formation of offixing carbon.

or liquid compound. In this zinc oxid. The reduction of pressure withinthe cell produced by the union of oxygen with hydrogen, zinc, or othersubstances is appreciable even when the cap contains air. The amount ofoxygen in the ca is inSufiicient to produce the harmful eii ects whichwould be caused by continued ingress of air, if the seal werenon-hermetic. In some cases, also, ammonia supplied as described above,may react to .form compounds with zinc chlorid or other cellconstituent, before having 0 portunit to combine with carbon dioxid. 1eresut of such reaction is a reduction of gas volume compensatin forsubsequent generation of gases in the cc 1.

When the cell is to be put in service, the sealing cap will bedisconnected as described and the spacing cup removed from its positionover the carbon pole. The serv ice characteristics of cells so protectedfrom the deleterious effects of access of atmospheric oxygen, or othercauses due to incomplete isolation from the atmosphere, will be foundsubstantially equal to those of freshly pre ared cells.

The above described ex ients for preventing gas pressure may b: usedsingly or in any desired combination according to the requirements ofany particular case. If gases other than carbon dioxid are given off inobjectionable quantities, a suitable spe' cifio absorbent for such gasesmay be read ily selected in accordance with known chem ical properties.Some of the beneficial results of my invention may be obtained innon-hermetically sealed cells, as, for exam' ple, by placing a layer ofgas absorbent material below the pitch seal. The shape and mode ofattachment of the sealing cap may also be modified to fit it for usewith cells of non-cylindrical type, and various other changes inconstruction and relative arrangement of parts may be made withln thescope of the appended claims.

I claim:

1. A dry cell containing a material capable of react-ing'chemicully witha substance in said cell to produce a reduction of pressure in saidcell.

2. A dry cell containing a material capable of preventing excessive gaspressure therein by chemical combination with gas evolved from cellconstituents.

3. A dry cell containing an alkaline ll) sorbent material capable offixing gas evolved in-said cell.

loss of moisture,

reacting chemically with gases generated in the cell.

7. lln a dry cell a hermetic seal comprising a cap having a volumeadapting it to serve as an expansion chamber for gases generated Withinthe cell.

8.; in a dry cell, a seal permitting the passage cf gases, an air-tightcap enclosing said. seal and a material in said cap capable of reaclinchemically with gases generaiecl in the cel 9. In a dry cell, a sealpermitting the passage of gases, an air-tight cap enclosing said seal,anol a material in saiel cap capable of reacting chemically Willi gasesgenerated in the cell, said cap having a top capable of yielding withoutrupture under gas pressure.

In testimony whereof, I allix my signalure.

GEQRGE HEISE.

